1. Technical Field
This device relates to improvements in sandblasting nozzles and valving elements associated therewith. Sandblast nozzles dispense a controlled and directed stream of abrasive granular material intrained in a fluid stream such as air. The abrasive nature of the stream tends to erode valve sealing elements as well as nozzles requiring frequent replacement of wearable parts and quick failure of a tight efficient seal.
2. Description of Prior Art
Prior Art devices of this type have relied on a variety of different valve configurations to control the fluid flow of abrasive materials in a dispensing fluid stream, see for example U.S. Pat. No. 2,054,517, Pat. No. 2,099,847, Pat. No. 3,618,263, Pat. No. 4,269,359 and U.S. Pat. No. 1,198,595.
In U.S. Pat. No. 2,054,517 a spraying device for dampening clothes is disclosed that uses a pivoted offset angularly disposed level arm with a spray tip and a stopper. The rubber stopper forms a valve element that is engageable over an opening or jet that dispenses the water. As the lever arm is moved the stopper is pivoted out of the flow path and the end of the offset lever is positioned within the flow path diffusing the water into a spray pattern.
Pat. No. 2,099,847 shows a dispensing apparatus that is characterized by a pivoted lever arm having a rubber closure element secured on its free end engageable in sealing relation with a nozzle. The device shows a valve element mounted within a fitting on the end of the lever arm and extending outwardly therefrom.
In U.S. Pat. No. 3,618,263 a sandblasting installation is shown which has a pistol-like blasting nozzle with a lever actuated shut-off mechanism. A wear plate of tungsten carbide is attached for sealing engagement with the nozzle. The wear plate is an integral one-piece construction.
Pat. No. 4,269,359 discloses a valve construction for use with high velocity streams of abrasive granular material, typical of sandblasting. A valve element is positioned on the end of a lever arm assembly and is comprised of a cylindrical element on a support shaft. The valve element distorts on engagement with the nozzle sealing same.
In British Pat. No. 1,198,595 an improvement in a sandblasting installation is shown which corresponds to U.S. Pat. No. 3,618,263 hereinbefore described.